Copper(I)-Catalyzed Asymmetric Addition of Terminal Alkynes to beta-Imino Esters: An Efficient and Direct Method in the Synthesis of Chiral beta(3)-Alkynyl beta(2,2)-Dimethyl Amino Acid Derivatives

The first catalytic asymmetric addition of terminal alkynes to β-imino esters was carried out using chiral copper(I) complexes as catalysts under mild reaction conditions, providing an efficient and direct synthetic approach to β3-alkynyl β2,2-dimethyl amino esters with yields of 73–97% and 48–90% ee. The rich chemistry of the alkynyl functionality makes the present method a powerful and versatile approach to a wide range of optically active β2,2-dimethyl amino acid derivatives.